MultiSelectListPreference example

Question

I am having a hard time trying to find a good example of the MultiSelectListPreference provided in the Android API. I have seen many references to this blog, and tho this is the end result I desire, I don't want to create a class for each multi-select preference I want to implement. Ultimately I want to see the preferences xml for a simple multi-select dialog (which i will populate the values for dynamically), as well to the call to addPreferencesFromResource(R.xml.preferences);

Currently, I have:

<MultiSelectListPreference     android:defaultValue=""     android:enabled="true"     android:entries="@array/pref_default_entries"     android:entryValues="@array/pref_default_values"     android:key="TargetList"     android:persistent="true"     android:summary="@string/TargetSummary"     android:title="@string/TargetTitle" /> 

and when I try to call addPreferencesFromResource in my Activities onCreate call I am getting the following error:

06-18 13:59:30.690: E/AndroidRuntime(6052): FATAL EXCEPTION: main 06-18 13:59:30.690: E/AndroidRuntime(6052): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tracker/com.tracker.TrackerActivity}: android.view.InflateException: Binary XML file line #37: Error inflating class java.lang.reflect.Constructor 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1818) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1834) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.ActivityThread.access$500(ActivityThread.java:122) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1027) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.os.Handler.dispatchMessage(Handler.java:99) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.os.Looper.loop(Looper.java:132) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.ActivityThread.main(ActivityThread.java:4126) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at java.lang.reflect.Method.invokeNative(Native Method) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at java.lang.reflect.Method.invoke(Method.java:491) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at dalvik.system.NativeStart.main(Native Method) 06-18 13:59:30.690: E/AndroidRuntime(6052): Caused by: android.view.InflateException: Binary XML file line #37: Error inflating class java.lang.reflect.Constructor 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.createItem(GenericInflater.java:397) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.onCreateItem(GenericInflater.java:417) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.createItemFromTag(GenericInflater.java:428) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.rInflate(GenericInflater.java:481) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.inflate(GenericInflater.java:326) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.inflate(GenericInflater.java:263) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:269) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:1366) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at com.tracker.TrackerActivity.onCreate(TrackerActivity.java:30) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1050) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1782) 06-18 13:59:30.690: E/AndroidRuntime(6052):     ... 11 more 06-18 13:59:30.690: E/AndroidRuntime(6052): Caused by: java.lang.reflect.InvocationTargetException 06-18 13:59:30.690: E/AndroidRuntime(6052):     at java.lang.reflect.Constructor.constructNative(Native Method) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at java.lang.reflect.Constructor.newInstance(Constructor.java:416) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.GenericInflater.createItem(GenericInflater.java:383) 06-18 13:59:30.690: E/AndroidRuntime(6052):     ... 21 more 06-18 13:59:30.690: E/AndroidRuntime(6052): Caused by: java.lang.NullPointerException 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.content.res.AssetManager.getResourceTextArray(AssetManager.java:215) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.content.res.Resources.getTextArray(Resources.java:435) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.content.res.TypedArray.getTextArray(TypedArray.java:628) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.MultiSelectListPreference.onGetDefaultValue(MultiSelectListPreference.java:210) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.Preference.<init>(Preference.java:257) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.DialogPreference.<init>(DialogPreference.java:69) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.DialogPreference.<init>(DialogPreference.java:90) 06-18 13:59:30.690: E/AndroidRuntime(6052):     at android.preference.MultiSelectListPreference.<init>(MultiSelectListPreference.java:49) 06-18 13:59:30.690: E/AndroidRuntime(6052):     ... 24 more 

I look forward to your reply!

Answer 1

You need to specify the defaultValues property

<MultiSelectListPreference         android:dialogTitle="@string/mode_repeat"         android:key="mode_repeat"         android:summary=""                 android:title="@string/mode_repeat"         android:entries="@array/weekdays"         android:entryValues="@array/weekdays_values"         android:defaultValue="@array/empty_array"         /> 

If you don't want default values, create an empty array in your strings.xml

<string-array name="empty_array"/>